Electron-stimulated modification of Si surfaces

Scanning tunneling microscopy studies show significant structural modifications that involved atom desorption and displacement following mild irradiation by electrons of 90-2000 eV. For Si(111) (7 X 7), adatom layer vacancies increased monotonically with incident energy. For Si(100)-(2 x 1), irradiation produced dimer vacancies, and ad-dimers as Si atoms transferred to the terrace. The modification processes are tied to the energy distribution of electron-hole and electron attachment states achieved by inelastic cascade scattering. Hence, beams previously believed to be benign induce surface structural modifications. [S0031-9007(99)08389-1].